Sight line horizon determining means



- y o. EPPENSTEIN 2,042,040

SIGHT LINE HORIZON DETERMINING MEANS Original Filed May 15, 1954 Invan/0r:

Patented May 26, 1936 UNITED STATES PArENr-or= ber 11, 1935, Serial May16, 1933 3 Claims. (01 33-7 3) I have filed applications in GermanyrMay1933; France, May 12, 1934 (Patent No. 773,222) Great Britain, May 14,1934 (Patent No. 425,939) Russia, May 15, 1934; Italy, May16,.1934-(Patent No. 321,035); Japan; May 16, 1934.

In my copending U. S. application Ser. No. 725,752, flied May 15, 1934,of which-the present application-is a. division, is-described aninstrument for carrying into practice a method of determining ahorizontal line through a point on board ship and at a known heightabove sea-level. In this method, thesought horizontal line is determinedby maintaining the elevation of a stereoscopic rangefinder on board'shipcontinuously so adjusted as to keep this rangeiinder permanentlydirected to a point in the sea-level and at a constant distance from thefinder, namely to the aiming point, the sought horizontal line beingdeduced from the consequent angle of elevation of the aiming point, atwhich angle the line connecting the rangeflnder and this aiming point,namely the sighting line, is inclined relatively to the said horizontalline. The said stereoscopic rangefinder contains a stereoscopic mark ata constant apparent distance and a device for indicating the variationsof that angle which is-included between the sighting line and a lineparallel to the ships deck and at right angles to the base of therangefinder. The said variations of angle, which are indicated by thedevice in the rangefinder, correspond to the oscillations of the ship ina plane at right angles to the base of the rangefinder and are equal tothe variations of the angle of elevation of the rangeflnder, which aredue to the said oscillations of the ship.

In the said case, it is assumed that the support for the apparatuseffects oscillations about one axis only, -viz. about an axis parallelto the rangefinder base. However, this is not the case in practice,since oscillations about two axes at right angles relative to each otherare generally concerned. The measuring results of the describedapparatus will consequently contain certain errors which may beneglected so long as the variations of the angles are comparativelysmall. The said errors may be avoided completely by determining andstabilizing not only a straight line but by stabilizing two straightlines conveniently intersecting each other at right angles, that is tosay a plane, which may be effected by using for the new method twoinstruments that have corresponding positions relatively to each other.

The present invention relates to sight line horizon determining meansand has for its object ring 51.

No. 49,227. In" Germany an especially simple apparatus for thestabilize. tion of the horizontal position of a plane surface of a. bodymounted on -board ship. -Accordingto the invention the apparatusconsists of twostereo'scopic rangefinders having stereoscopic marks at aconstant apparent distanceand being rigid- 1y connected to each other'insuch a manner that the bases of these rangeflnders lie in a planeparallel to the plane to be stabilized and intersect each other, therangefinders: being 'cardanicaliy so mounted on board ship thatrotations of the rangefinders about the one Cardan axisentailcorresponding variations of the elevation of one rangefinder, andthat rotations about the other Cardan axis entailcorrespondingvariations of the elevation of the other rangefinder. Bymeans of the said apparatus, a correct stabilization of instrumentsmounted on board ship may be effected regardless of what oscillationsthe ship is exposed to.

The accompanying drawing represents a constructional example of theinvention. Figures 1 and 2 illustrate the example in elevation and intop view, respectively. Figures 3 and 4 show parts of the example, thesetwo parts being seen in the directions of the arrows B and 0,respectively, of Figure 2.

The constructional example (Figures 1 and 4) shows the application ofthe invention for stabilizing the horizontal position of a plane. Theapparatus consists of two stereoscopic rangefinders 53 and 54 which areadjusted to a predetermined distance and whose bases lie normally in aplane parallel to the plane to be stabilized. The axes oi?v the basesextended intersect each other at right angles. The lines of sight of therangefinders 53 and 54 are inclined at an'angle of elevation arelatively to the plane determined by the bases. The rangefinders 53 and54 are rigidly connected to each other by means of a piece 55 rotatableabout an axis 58 in a Garden The axle 56 is parallel to the base of therangefinder 54. The Cardan ring 51 is rotatably mounted in bearings 58which are provided on board ship and whose axis is at right angles tothe axle 56 and, consequently, parallel to the axis of the rangefinder53. The piece 55 has a counterweight 59 which makes the centre ofgravity of the parts rigidly connected to the piece 55 lie at the centreof the Cardan bearing. A toothed wheel 60 having a fixed shaft GI and ahand wheel 62 is rotatably mounted on one of the bearings 58. Thetoothed wheel 60 meshes with a toothed segment 63 on the Cardan ring 51.The toothed segment 63 has a graduation 54 1 index H on the ring 57.

which cooperates with an index 65 attached to the bearing 58. The axle56 has a bevel wheel 66 which meshes with a bevel wheel 68 provided ona. telescope shaft 61.; The telescopeshaft 6'! ends in a hand wheel 69.The shaft 56 is provided with a graduation I0 cooperating with an Thehand wheels 62 and 69 lie below the rangefinders 53 and 54,

respectively, in such a' manner that they may be easily operated whenobservations are ef-v fected by means of the rangefinders, When usingthe apparatus, the observers at the rangefinders 53 and 54 are-to rotatethe hand wheels 62 and 69 in such a manner as to,

keep the rangefinders continuously directed to a point which lies at thepredetermined distance on the sea-level. The piece 55 and the partsrigidly connected to same are thus stabilized with respect tooscillations of the ship. The variations of the angles of, elevation,which. correspond to the oscillations of theship, may be read at: any

time on the graduationsfit and 10, where they are indicated by theindices 65 and 12, respectively.

Instead of these reading devices any mechanical or electric transmissiondevices of the known kind maybe connected to theapparatus, by. means ofwhich the variations of the angles of elevation may be continuouslytransmitted to board ship i for instance to stereoscopic rangeflndersrigidly connected to each other andhaving stereoscopic marks at aconstant apparent distance, the bases of the rangefinders lying in oneplane and being at right angles relatively to'each'other; means mountingrespectively for controlling and indicating the angular movements ofsaid finders about the respective Cardan axes.

2. In an apparatus according to claim 1, the said body being rigidlyconnected to the said two rangefinders, the weight and the arrangementof the bodybeing so chosen that the resulting centre of gravity of thetwo rangefinders and the other parts rotatable about the said two Cardanaxes lies approximately at the point of intersection of these axes; t

3. In an apparatus according to claim 1, 'two gears for respectivelyrotatingthe two said rangefinders about thesaid two Cardan axes,a'driving member so connected to each of the gears that an observerusing a respective rangeflnder may operate by hand'during theobservation that one of thetwo driving members whose operation effectsbodily movement of the used rangefinder.

o' rro 'EPPENS'I'EIN.

ations of the elevation of the other rangefinder, I and two devicesconnected to said Cardan axes

